Bridge KVM duplicated mac address

[luquee]

Hi

I have installed centos 7 kvm and virtualized with a virtual machine with elastix.. use the kvm host bridge

When I give the host with the kvm command brctl showmacs br1 shows me the following

port no mac addr is local? ageing timer
3 00:0b:82:0c:e2:5f no 10.82
3 00:0b:82:6a:89:71 no 116.32
3 00:0b:82:6a:89:78 no 90.43
3 00:0b:82:6a:91:8e no 135.26
3 00:0b:82:6a:91:8f no 3.08
3 00:0b:82:6a:91:90 no 54.27
3 00:0b:82:6a:91:93 no 93.16
3 00:0b:82:6a:91:94 no 1.00
3 00:0b:82:6a:91:97 no 106.90
3 00:0b:82:6a:91:98 no 16.08
2 52:54:00:7c:23:fa no 14.02
1 52:54:00:92:f9:47 no 1.01
3 c4:6e:1f:03:f9:0c yes 0.00
3 c4:6e:1f:03:f9:0c yes 0.00
3 d0:7e:28:9b:88:20 no 53.13
2 fe:54:00:7c:23:fa yes 0.00
2 fe:54:00:7c:23:fa yes 0.00
1 fe:54:00:92:f9:47 yes 0.00
1 fe:54:00:92:f9:47 yes 0.00

As you can see local macs me the sample duplicates if i ran the command arping from the kvm host to a virtual machine that has the ip 10.10.50.1 shows me


[root@servervirt ~]# arping -D -I br1 -c 120 10.10.50.1
ARPING 10.10.50.1 from 0.0.0.0 br1
Unicast reply from 10.10.50.1 [52:54:00:92:F9:47] for 10.10.50.1 [52:54:00:92:F9:47] 0.579ms
Sent 1 probes (1 broadcast(s))
Received 1 response(s)

arping to another host in lan

[root@servervirt ~]# arping -D -I br1 -c 120 10.10.50.11
ARPING 10.10.50.11 from 0.0.0.0 br1
Unicast reply from 10.10.50.11 [00:0B:82:6A:91:8E] 1.089ms
Sent 1 probes (1 broadcast(s))

I ask for help because I have problems with network latency everything else works fine and that's the only thing I see Normal
thanks

[aks]

Did you clone the VM?

[luquee]

Hi
No never clone the vm. I installed from gui virt-manager and put to the os bridge

[aks]

I only asked because, (if I remember right), by default a new MAC is not generated on a clone operation.

Are the two MAC addresses the same machine - in which case I'd guess that it's some kind of transitive thing. If it is the same machine, it doesn't really matter - in the sense that data destined to that MAC will go there and only to there. What do the VMs say? Does any one of them "think" there's a duplicate MAC on the network?

If there aren't duplicate (in the sense of two (or more) machines with the same MAC address) and the bridge still shows the duplicate(s), it could be a minor bug. Personally I'd log it and ignore the issue as it should have no effect.
If there are two (more more) machines with the same address then that's a really bad thing. I'd log an bug, remove the NIC from N-1 (where N is the number of machines with the same address) , add a new NIC to give them all a new MAC address.

Personally, I think I'd log bug to the virt-manager people.

[luquee]

hi

when income from the kvm server that is having the bridge command arp -a does not show me the mac duplicate is very likely a bug in virt-manager

thanks for your answer